2nd battery + solar and electrical work for a Chevy Suburban

[JimNcCO]

I'm thinking installing a solar/house battery system for my 2012 Chevy Suburban.

I'm not brand new to solar but have just a little bit of experience. Back in 2018, I installed two Renogy panels on a travel trailer with a PWM charger and two AGM batteries. I recently upgraded the trailer setup with two LiTime LiFePO4 batteries and a MPPT charger.

I have been researching this on my own for awhile, just found this forum today. The Suburban already has a second battery tray behind the grill on the driver side. Current thought is the following:

• One 100W LiTime LiFeO4 group 24 battery mounted on the second battery tray.
• Renogy 50A DC 2 DC / MPPT charger connected to the starter battery. The charger when set to lithium will stop charging at 34' F and resume charging when temperature rises to 37' F , so will not damage the battery. Will need to mount the Renogy very close to the battery for the temperature sensing to be similar to the battery's temperature. I live in Colorado and in the winter can get down to -20F. I certainly don't want to the battery to be charging when that cold, but hoping that once the big 6L engine is running for 10 to 20 minutes, the engine bay will get warm enough to start charging. The Renoge charger will split 50/50 between solar and alternator, so each side will take a maximum of 25 amps. The Renogy charger will also trickle charge the starter battery when the house battery is at 100%, which is a benefit when we are not driving the Suburban for a few weeks at a time between trips.
• 100W Renogy panel mounted on the roof rack cross bars just behind the sunroof. Run the wire down the side of roof and next the windshield using the magnetic wire holders into the engine bay to the Renogy charger.
• This last part is still a mystery to me. In an ideal world, I want to connect the Suburban's accessories (12V outlets, radio, interior lights) to the house battery. This not only allow me to run 12V fridges off the 12V outlets, but also will protect the starter battery in case the interior lights and other stuff get left on by accidents. The Suburban's 12V outlets are always hot so it's easy to leave things connected and draw power with ignition off. I downloaded the electrical diagram for the vehicle but really can't figure out what wires/switches to change. If I can not do this, then plan B is run wires from the house battery in the engine bay, through some gromets in the firewall, under the door sills, into the trunk area to a new 12V outlet. Or I can disconnect the wires to the existing 12V outlet in the trunk and connect it to the house battery wires.

Misc info: I do already have an EcoFlow Delta 2 power station. I can power the 12V fridge with the EcoFlow. I can charge the EcoFlow via the 12V outlet at about 120 watts when the engine is on. On certain trips when driving only about an hour a day, this doesn't not keep up with the fridge usage. To charge faster from the alternator, I'll have to install an 12-24V converter connected directly to the starting battery to charge the EcoFlow faster. I also have a Jackery Solarsaga 100W panel laying around. It's pretty efficient but is not waterproof and can not be left outside to charge if I'm not sitting around watching it, which is the case most of the time on our trips. Someone can grab it easily or wind can blow it away easily. I played with putting the Solarsaga under the windshield and found that the panel will only generate about 40% of power compared to sitting outside. Installing a separate independent system with house battery and roof solar in the Suburban will be much cleaner, zero effort to manage (even my wife can use it without knowing anything), and leave more space in the trunk for all the junks we like to bring on trips..

Would love to hear other people who have done similar setup and how it went, especially the wiring of all the accessories in the vehicle to the house battery, and any feed back on my plans. Thanks in advance!

 

[Browneye]

Personally I like the idea of running a serperate circuit back to where you need power, and setup a terminal/fuse block to power things instead of cigar lighter which is limited to about 10A. Your Delta can be set for faster charging that way, and you can run multiple devices.
XT60 plugs are handy and easy to make, will handle lots of amps. And there’s always the SAE plugs as an option as well.

Keep in mind your 100W panel will only put out about 5A or so on a good day - I have one hooked up to parallel starting batteries in the motorhome to maintain them. The house circuit is seperate, LFP and 500W of solar, and Orion dc2dc, and LFP charger for when I have access to 120VAC plugged in or with generator. Depending on your loads/draw you might want a larger panel or a couple of the 100’s.

Be sure to run sufficient wire gauge for your loads. And depending on your usage, the second battery might even be better as an agm, they’re easy to maintain and not affected by cold temps. If you have access to power when it’s really cold you can put a battery warmer in - I do that for my RV starting batteries that are in an outside bay for temps below freezing. But the coach is plugged in when parked.